This invention relates to over-the-road vehicles. More particularly, this invention relates to tractor-trailer couplings which serve to control relative pivotal movement allowed between the tractor and trailer to facilitate easy handling of the vehicle in tight maneuvering situations, but which greatly reduces the possibility that the tractor and trailer can jackknife.
This invention can be used in the manufacture of new tractor-trailer vehicles, and can be readily incorporated into existing vehicles. In either case, the invention involves a relatively small amount of expense while providing for safe and maneuverable vehicle operation and reducing the likelihood of vehicle damage.
Conventional tractors and trailers are coupled together for over-the-road operation by a fifth wheel on the tractor in which a king pin on the trailer is pivotally received. This coupling allows the tractor to pull the trailer and allows relative pivotal movement therebetween for maneuvering the vehicle.
A recognized problem with vehicles of this type is that of jackknifing. This occurs when the trailer pivots relative to the tractor to a point where the operator can no longer maintain or recover control of the vehicle.
When these vehicles are in a tight maneuvering situation, it is desirable that the tractor and trailer be able to pivot relative to one another to a somewhat greater extent than is considered necessary or safe when the vehicle is on the highway. However, the allowed pivotal movement in tight maneuvering situations should not be so great that the tractor and trailer sides can contact each other and cause damage to the vehicle.